1. Field of the Invention
The present invention relates generally to an apparatus for opening the rotating discharge doors of a railway hopper car, and in particular, to an apparatus for manually opening the rotating hopper car discharge doors from either side of the hopper car by a single operator.
2. Description of the Prior Art
A common type of railroad freight car in use today is the open top freight car of the type wherein the load may be discharged through hoppers on the underside of the body. Such cars are generally referred to as hopper cars and are used to haul coal, phosphate and other commodities. After hopper cars are positioned over an unloading pit, the discharge doors of the hoppers are opened, allowing the material within the hopper car to be emptied into the pit. There are several methods available for opening and closing the hopper doors.
U.S. Pat. No. 3,596,609, issued to Ortner et. al., describes a system for simultaneously opening rotating hopper doors using a longitudinally extending operating rod connected to actuating shafts extending transversely below the hopper car body. Each door operating lever rotates an actuating shaft which in turn actuates a linkage mechanism to open and close the doors.
U.S. Pat. No. 4,741,274, issued to Ferris et. al., also describes a system for operating hopper dump doors on a railway hopper car. The lever is comprised of a single plate body portion with pivotal connections. The pivotal connections are coplanar with the door operating struts in a substantially vertical plan passing through the vertical transverse centerline of the center sill of the car to eliminate unnecessary rotational movements of the mechanism.
Other prior art references that teach operating mechanisms for opening and closing hopper doors include U.S. Pat. No. 3,187,684 to Ortner; U.S. Pat. No. 3,611,947 to Nagy; U.S. Pat. No. 3,786,764 to Beer et al.; U.S. Pat. No. 3,815,514 to Heap; U.S. Pat. No. 3,818,842 to Heap; U.S. Pat. No. 3,949,681 to Miller; U.S. Pat. No. 4,222,334 to Peterson; U.S. Pat. No. 4,366,757 to Funk; U.S. Pat. No. 4,601,244 to Fischer; and U.S. Pat. No. 5,823,118 to Angstrom. There are several disadvantages to the hopper door operating mechanisms described in some of the above-cited patents. One problem is that some of the prior art mechanisms are designed such that each actuating mechanism is connected to doors from two separate hoppers. Thus, if the mechanism fails, it effects the operation of two hoppers. Another disadvantage of some of the above described hopper door mechanisms is that, since the mechanisms are designed to operate doors from two adjacent hoppers, the mechanisms must push the doors closed with compressive forces being delivered to the mechanisms. This design makes it necessary to periodically adjust the mechanism as the system wears. In addition, the compressive forces applied to the hopper doors in closing may cause buckling problems. A further disadvantage of some of the above-described hopper cars is that the operating mechanisms limit the distance of the door motion, thus limiting the open area of the car bottom. This arrangement slows the unloading process and causes additional costs and potential damage to the car such as due to increased periods in thaw sheds.
Another prior art reference is Applicant""s earlier U.S. Pat. No. 5,249,531 (hereinafter referred to as xe2x80x9cApplicant""s earlier ""531 patentxe2x80x9d) entitled xe2x80x9cRailroad Hopper Car Door Actuating Mechanismxe2x80x9d, which issued on Oct. 5, 1993.
I addressed these problems in developing the railroad hopper car door actuating mechanism described in my earlier ""531 patent (hereinafter referred to as xe2x80x9cmy earlier ""531 patentxe2x80x9d) which is incorporated herein by reference in its entirety. The door operating mechanism described in my prior patent does not provide for manual operation.
It is an object of the present invention to provide a manual mechanism for actuating the discharge doors of a hopper car which maintain some of the advantages of my prior invention. It is also an object of the present invention to provide a door actuating mechanism which does not need periodic adjustment to allow for wear of the parts. It is a further object of this invention to provide a door operating system for a hopper car in which the closing and lockup of the hopper doors are in tension, as opposed to compression type mechanisms. It is a further object of the present invention to provide a system which provides a significant opening in the bottom of a hopper car in order to allow quick and safe discharge of its contents. It is a further object of the present invention to provide a door operating system in which each door assembly has a positive over-center locking mechanism. It is a further object of the present invention to provide a mechanism that can be retrofitted into existing hopper cars as well as incorporated into new construction.
These and other objects may be accomplished by the manual railroad hopper door actuating mechanism of my invention. The manual railroad hopper door actuating mechanism includes a manually rotatable door actuation shaft that is accessible from either side of the railcar. The door actuation shaft rotates a first pivot arm that is coupled to a second door actuating pivot arm through a first linkage arm. A second door actuating linkage arm extends between the pivot connecting the first linkage arm and the second pivot arm and the hopper door pan for actuating the door. Rotation of the actuating shaft in a first direction will open the hopper door and rotation in the opposite direction will shut the hopper door. The door operating mechanism maintains the over-center closed configuration described in my earlier ""531 patent.
These and other advantages of the present invention will be clarified in the brief description of the preferred embodiments together with the attached figures wherein like reference numerals represent like elements throughout.